Improved modification of yeast uricase with polyethylene glycol, accompanied with nonimmunoreactivity towards anti-uricase serum and high enzymic activity

Abstract

The highly purified uricase from Candida utilis was modified with 2,4-bis(O-methoxypolyethylene glycol)-6-chloro-s-triazine (activated PEG2), which was synthesized from monomethoxypolyethylene glycol (MW 5,000) and cyanuric chloride. Modification of approximately 36 out of the total 98 amino groups in the uricase molecule led to the complete loss of the binding ability towards antiuricase serum from rabbit with the retention of high enzymic activity (45% of native uricase). The modified uricale cleared more slowly from the plasma of mice compared with native uricase.